Process for preparing monochlorodifluoro acetyl fluoride



Patented Apr. 27, 1954 PROCESS FQR raemnmo MONOGHLQRO- DIELUORQLACETYUFLUQRIDE Vic or. B'- Hur a We e Del as nor o 1 E. L'du 'rr st a semo rsa" Cbm'iiany,".Wil1- i9 De a e m? 9 wares N Drawing. Application. February 8, 1952 .Serial.No.270,7 f

2 Claims. (01. 260-544) results. Such processes are, illustratedby Eatents 2,439,505- and 2,456,763 .grantedto David W.

Chaney. g

.It is an obiecbofmy invention to produce monochlorodifiuoro ;acety1 flu ride. which. i a new chemicalcompound having valuable propertiesparticularlyfor:use as an intermediate in the preparation .of othervaluable compounds.-. An.- otherobject is to provide-a novel processjfor the preparation of; monochlorodifluoro ,acetyl fluoride. ,A furtherobjectisto provideaprocess for producing monochlorodifluoro acetylfluoride in a simple and safe-manner. Stillturther objects are to. provide anew .compositionof matter andto advance the. art. Still. other. objects Wi1i;app ear hereinafter.

The abovend other-objects may .be an p1ished.in,accordance with my-inventi comprises .oxidizin ....1,1,2:triflu 2.- y ne, ;CF2;CEG1. wit o en. in 11 116 .alosence of a catalytic agent at a temperature of fromabout. 25 .0; to about 50 C. and. under a pressure o iromabostlqqzi -abesifi pounds per square inch gauge. By such process, monochlorodifluoro acetyl i'luoride f is produced; v pied yields in a simple and'sfi fema I v V ;Mono'chlorodif1uoro acetyl 'iluo de ha sf,,t l 1 formulaCFaGlCOFand boilsat i han e rea and: in r tion in isasequ stat liquefied with a reasonable degree of refrigeration, if desired, and...';rleadily -handled and used in reactions as a liquid. ltsboiling poin advantageous in many cases, sermons it is used as a reagent, because any unreacted material can be easily removed from the reaction mixture by volatilization. It is a valuable intermediate for the preparation of monochlorodifluoro acetic amides and esters, to which it is readily converted by treatment with the appropriate amine or alcohol. Also, it hydrolyzes readily with water to give the valuable monochlorodifiuoro acetic acid, thus providing a new synthetic route to such valuable acid.

Wh e th oxida ion of QF C 1939" chlorodifluoro acetyl fluoride anbe carried outin a simple manner it ises nt a t h d vtions be carefully controlled. Ordinarily, the CE2:CFC1.will be ,placed in a vessel capable of withstanding several hundred pounds pressure, such as an,autoclawe, which has provision for a itat o nd co n because-t e fii fli i .oth rmic- Ox en th n forc d 11. 1 0 h ve to a ressure of fr m ab u 0 o ab 3 pou d pe quar no gau e w l h ooni m areasitat o e em ra ure isho ai f iom abou .2 C- t abou 50 .0 Usu l th CF2:CFC1 will be at a temperaturebelovv 25C. and frequent y. below itsboi in po nt-( 2 .9? Q ndhea nswi l beappliedto the vessel to bring the material Iup tothe desired reaction temperature to startthe reaction, andthen cooling will beapplied tothe vessel, as by, circulating a coolingfiuidpver its outersurface, to maintain the temperature in the vesse w t th des red range. When the absorption of oxygen ceas'e s, as shown bythe ai u of the press re t p in ther therreaction is complete. Then the contents of the vesseLare withdrawn through a condenser oo edt hout ,-'I C-. 9;app. wh r u o the rud p od ct is nd n ed. d ool eotedias .a iqui Unreao ed QFZ QI an any .side re cti n pro uc s are na to ed ,irom theumonooh o o ifliwm acety fl rid by f e tional distillation.

Theproportionof. oxygensemployed is not critical, but should be at least 0.5 molar proportion.

Usually,,a.-considerable excess .of oxy en .i employed so asto ensure maximum contact of the f,CFz: CF,'Ql-therewith with optimum yieldsina min m .o e Th max mu amo nt. f

oxygen is limited solely by considerations ofconynience -and economy. The total amount of oxygen may be added all at once, but, preferably, is added continuously to' the"vessel as rapidly as it isusedup inthereactionand soas to main- =tain, the desired pressure voris added in increments sothat-the pressure ,isbuilt uptoadesired highzlevellandthen. allowedtoifall to a desired lower level before each additional increment is added.

It is known that light and chlorine catalyze the oxidation of olefinic compounds. While catalytic agents, such as light and chlorine, have been required heretofore in such oxidations, I have found that such oxidizing agents cannot be used in my process, but must be carefully excluded therefrom. When it has been attempted to oxidize CF2=CFC1 in the presence of catalytic agents, such as light, chlorine, tertiary butyl hypochlorite and combinations thereof, a violent uncontrollable reaction takes place with incandescence or burning and the production of carbon, halogenatedmethanes and phosgenes without the productionof the desired monochlorodifiuoro acetyl fluoride. u

Such violent uncontrollable reaction also takes place. at high temperature and pressures. Accordingly, in order to carry out the process safely and successfully without difliculty, the temperature and pressures should not materially exceed 50 C. and 300 pounds per square inch gauge.

In order to more clearly illustrate my invention, preferred modes of carrying the same into effect and the advantageous results to be obtained thereby, the following examples are given:

Example I Into a pressure vessel, equipped for agitation and cooling externally with water, was put 106 parts by weight of monochlorotrifluoroethylene, CFQ CFCI. The autogenous pressure was 70 lbs. per square inch gauge at C. Oxygen from a cylinder was then passed into the vessel until a pressure of 125 lbs. per square inch gauge was attained. The oxygen flow was turned off. Agitation was then commenced. The temperature of the reaction mass increased gradually from an initial point of 25 C. to 46 C. after 3 hours, and

then fell to 37 C. after a further 3 hours. The pressure increased to 190 lbs. at the end of minutes and then fell gradually to 110 lbs. at the end of 6 hours.

The gaseous contents of the vessel were released slowly through a valve and passed to a refrigerated condenser and collected at a temperature of C. to C. The residual gas in thevessel was collected in a trap surrounded by liquid nitrogen by evacuating the vessel to about 1 mm. absolute pressure. A total of 92 parts by weight was ius collected.

The product was fractionally distilled to obtain the product, CFzClCOF, which boiled at 18.5 C. The yield was approximately 43%. The product was characterized by converting it to the amide by dissolving it in ether and passing gaseous ammonia into the solution. The amide was recovered from the ether as a white crystalline solid and showed the following analysis as com- Example II In another experiment in the same equipment, 93 parts by weight'of CF2=CFC1 were put into the vessel and oxygen was added in small increments over 22 hours (the elapsed time was 67 hours counting idle overnight periods) until a final pressure of 272 lbs. per square inch gauge had been attained. The temperature was held at 27-37 C. during this time. The gaseous contents of the vessel were discharged into cold traps and totaled 93 parts by weight. Analysis by infrared absorption spectra showed the presence of 50.8% CFzClCOF.

It will be understood that the preceding examples have been given merely for purposes of illustration and that my invention is not limited tothe specific embodiments disclosed therein. It will be apparent to those skilled in the art that variations can be made in the conditions and proportions employed, within the limits hereinbefore set forth, and in the equipment without departing from the spirit or scope of my invention.

From the preceding description, it will be apparent that, by my invention, I have provided a valuable new compound, monochlorodifluoro acetyl fluoride, and a novel, simple and effective method for preparing such compound. Accordingly, it will be apparent that my invention constitutes a valuable contribution to and an important advance in the art.

I claim:

1. The process which comprises oxidizing with oxygen in the absence of a catalytic agent at a temperature of from about 25 C. to about 50 C. and under a pressure of from about to about 300 pounds per square inch gauge, and then separating monochlorodifiuoro acetyl fluoride from the reaction mixture.

2. The process for preparing monochlorodifluoro acetyl fluoride which comprises placing CF2=CFC1 in a pressure vessel, adding at least 0.5 molar proportion of oxygen at a pressure of from about 100120 about 300 pounds per square inch gauge, heating the mixture with agitation to a temperature of from about 25 C. to about 50 C., maintaining the temperature within the range of from'about 25 C. to about 50 C. and the pressure within the range of from about 100 to about 300 pounds per square inch gauge until the absorption of oxygen by the CF2=CFCI ceases, excluding lightand other catalytic agents from the reacting materials throughout such process, and then recovering the reaction products.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,976,265 Mugdan et a1. 1 Oct. 9, 1934 2,062,743 Daudt et a1 Dec. 1, 1936 2,257,868 Tinker Oct. 7, 1941 2,378,048 Theobald June 12, 1945 2,480,467 Haworth Aug. 30, 1949 Diesslin et al Sept. 4, 1951 OTHER REFERENCES Beilstein, vol. 2, page 206. 

1. THE PROCESS WHICH COMPRISES OXIDIZING 